Fuse for high-explosive shells.



ii. soHLMAN, H. NORDENPELT & H; MOREN. EUS-B FOR HIGH EXPLOSIVE SHELLS.

APPLIOATION riLnD ssn. 1, 1910.

Patnted Feb; 6, 1912 UNITED STATES PATENT OFFICE..

RAGNAR SOHLMAN, HENRIK NORDENFELT, AND HUGo MoRN, or Boreas, SWEDEN.

FUSE FOR HIGH-EXPLOSIVE SHELLS.

Patented eb. 6, 1912.

Application led September 1,` 1910. Serial No. 580.091.

To all whoml it may concern:

Be it known that we, Raon-m SOIILMAN, managing director, Hanau; Nonnnxrnur, assistant director, and Hoo Momx. en grincer, subjects of Sweden. residing at Ilofors, Sweden, have invented new and useful lmprovements` in Fuses for lligh-Explosive Shells, of which the following is a specification.

The present invention relates to a new and improved safety device adapted to prevent the occurrence of premature explosions ot high explosive shells.

The modern high explosives used for armor-piercing shells and common shells (such as trinitrotolmil or similar nitro conn pounds). require. as is well known. a very powerful percussive shock in order to develop their full explosive effect. Such shock is usually imparted to the bursting charge by a .large detonator, which detonates a charge of moderately compressed picric acid. trinitrotoluol` or thetlike. The use of such large detonators. which must be composed at least in part of a comparatively' sensitive fulminate mixture. is. however, accompanied by a certain element of danger. as the detonator may in some cases owing to defects in manufacture or other unforeseen circumstances explode on the discharge of the shell from or while within the gun. thus causing a premature explosion. To avoid the danger resulting from such accidents some fuses for high explosive shells have the percussion cap placed in a speciall)Y strong chamber sepcrate from the detonator of the fuse in such a wa)T that a premature explosion of the percussion cap cannot be communicated to said detonator. The percussion cap is brought into its final position bv the impact on striking' against the object aimed at. or in some cases b v the rotation of the projectile. or by the expansion of a compressed spring1r in point or head fuses) carrying the detonator ofltlie fuse in a position near to the percussion cap. where it mav be exploded bv the tiring of the latter. These devices have however various drawbacks: this is especiall)r true in connection with the use of com; pressed springs as hitherto practiced for the purpose of effecting the said movement of the detonator, these being very unsatisfactory and unreliable. A spring resting in a compressed state for years gradually loses its elasticity and may 'not be relied upon -to expand with its original force; on the other hand, no satisfactory deviceof this'kind i has been proposed forloas'e fuses, where the problem of causing the fuse tobecomeV operative h v the diseharp'e ofytlleshcll is'somcwhat diticrent and in' sonic respects moro rliflicult than in connection Awith point or head fuses.

The present invention lr'o'iisifsts in principle in the employment of a movable meniher in the si'f' Je ot' arod or airing'. which is held in position h v a` disk or the like with protruding arms. or by a pin. or `in some other suitable wav` so that the inertia of the movable member.' when the projectile is suddenlv started in motion bv the discharge of the gun. is sufficient to overcome the resistance of the arms of the ring aforesaid. or to shear the pin holding it. and thereupon to cause the compression of a "spring placed in the rear ot the movable me'm'ber: as loneY as the acceleration of the sliell continues. that is. as long,lr as the shell movesV in the bore ot the `gun. and someTshorbdistance infront of the muzzle. the said spring"v 'is kept under compression bv the inerti'a" of the movable member: but when; the acceleration stops the springreturns to its initial po=ition. The return movement of the spring is utiliied to bring: the primer into such position relatively to the detouat'or ot' the fuse that it mai7 explode the latter on being tired.

In the aceompanving drawing* Figures 1 to 6 show three different embodiments of the invention in longitudinal section: Fins. L 3 and 5 showinpr the shells in inoperative position and Figs. 9.4 and. G showing them in operative position Referring to Figs. 1 Vand 2. n is the movable member. which 'is held in position hv a rino or disk 7) having"Toul1v Iarms restingr against the edge of theibore of thcrccess e in the primer carrie'rfafThe otherA end of the said carrier contains theprimercharfre t'. 0n discharge of the; Leung lthe inertia of the member n causes considerable p1-e sure to be 'exerted on the disk' 7) so lthat its arms vield and allow the-spindle of the' mcinber n to enter into the recessjnt-he carrier-ff. llu this movement the i'nelflbe'rvr @compresses the helical spring 71. When-the acceleration ot the shot ceases. therin'gr:Izreturns "to its normal position carryiiigl'` with litt'hefn'icmher a. as the armani-th| dislr'f) ,-whcnforciiil into the recess of Ythe.ca1'j,i;ijeile*'lifo'litl thaise-3nuits a and c tirmlvtogethenf"ngftlie '.z'itovement of the member n being C'. 'iiitted to the primer carrier, the parts-"occiipfv t'lie position shown in Fi". 9 On striking against the `object aimed at the flame from the per? In Figs. 3 and 4, the movable member a is of annular formation and is held in position by a four armed disk b which arms are compressed by the pressure due to the inertia of the ring, when the projectile is started in motion. In moving backward the ring a compresses the helical spring h and finally forces the arms of a second disk d to contract within the bore of the ring a. The disk d is thus connected with the ring 'a andwhen the latter again moves forward, owing to the return movement of the spring h, the disk al' and the primer f are also carried forward into the firing position.

In Figs. 5 and 6 the ring aV is held in itsl initial position by the four arms of a disk b protruding into the bottom part of t-he primer carrier. The operation of this arrangement, as shown by Fig. 6, is similar to the p eceding modification.

`In so ie fuses the force of the primer when exploded in due course by the detonation of a percussion cav k and of an intermediate primer l of suitable power, may however be greater than if the primer explodes directly b the concussion on the firing ofthe round. It may thus present some diliiculties to produce a casing strong enough to resist, with absolute impossibility of cracking, the detonation due to a premature ignition of the percussion ca'p Zi and communicated in regular course through the intermediate primer l to the large primer f, whereas the casing may be quite strong enough to resist the less powerful detonation of the primer f due to direct percussion (in connection with a faulty manufacture ofthe primer). To avoid'this difficulty we have combined with the arrangement for causing the fuse to become operative` as vhereinbefore described, a 4second safety device, operated by the same movable parts, and acting in such a way that communication of the Haine from the percussion cap 7c is shut off until the jectileA ceases, that is, has` left the gun. This safety arran ement may be varied in different ways. igs. 3, 4 and 5, 6 show two' modifications thereof. In Figs. 3 and 4 thecoml'nunication of flame ,from the cap k is"fnormally shut off by 'a accelerationof the prountil .the projectile tion u which fits into a recess z in slide valve n which yis held in in o or the like connected wit the disk d.

Vhen the disk d is carried forward as heremovement L the said slide valve 'n isreleased and 1s forced outward by the centrifugal force due to the rotation of the projectile, thus leaving the communication of flame open from the cap la. In Figs. 5 and 6, the casing of the primer f is provided with a lid r, carrying a tubular prolongathe body inbefore described by the return of the spring of the fuse.

The acceleration of the projectile, when moving in the bore of the gun, causes the detonator to exert a certain pressure on the lid r and tube o and thus insures a perfect tight fit of the latter in the recess 2. If the cap and intermediate primer l are accidentally fired in this position, the detonation is therefore :not communicated to the large primer f.

Havin now nature o our invention and the manner of its operation, what we claim is:

1. In percussion base fuses for shells, the combination with a fixed detonator charge and a movable primer charge which is normally positioned in a strong chamber behind and separate fromI the detonator charge, of an inertia operated member and a spring positioned behind `the same adapted to be compressed by the movement of said member during the acceleration of the projectile, said movement of said member operatively connecting it with the movable primer charge, whereb the latter will be moved forward in active position by said spring.

2. In percussion base fuses for shells, the combination with a fixed detonator charge and a movable primer charge which is normally positioned in a strong chamber behind and separate from the detonator charge, of an inertia operated member adapted to be operatively connected to the movable primer charge during the acceleration of the projectile, a spring positioned behind said member, and a safety device normally shutting off communication between the percussion cap and the primer charge, said safety device being"4 released by the return movement of said spring.

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

RAGNAR SOHLMAN. l i HENRIK .NORDENFELT. Y HUGO MORN. Witnesses:

H. TBLAUDER, D. DAHLs'raM.

osition by a I Particularly described the F5 so I 

